The 2003-04 season was the hardest ever for Leganes fans, even though it might have seemed different to an onlooker. After all, they were making the biggest headlines and set themselves the most ambitious target.

Daniel Grinbank, a wealthy Argentine music producer, acquired a stake at the club in the summer of 2003 and promised to make extraordinary investments in order to get promoted to Primera Division for the first time. He appointed Jose Pekerman, the famous Argentine coach who guided his Under-20 national team to three World Cup triumphs, as the sporting director and the leading figure of the project. The squad was strengthened by signing intriguing new players, including veteran Argentine defender Jose Chamot from AC Milan, and even journalists outside of Spain started to write about Leganes.

And yet, for the locals it was a tragedy, because they felt that their beloved club had been stolen from them. Grinbank didn't care about the heritage and pride of the team from the blue-collar Madrid suburb. He released 17 Spanish players and brought 15 Argentinians in their place. Chamot was the biggest name of them all, but few Leganes faithful had heard about the likes of Lucas Alessandria, Santiago Kuhl and Bernardo Leyenda. In fact, they didn't want to hear their names at all. The very soul of the club had been brutally and mercilessly ripped out.

"I cannot forget those days," Marco Antonio Sanchez, a lifelong Leganes fan, tells ESPN FC. "We didn't support the decision to bring in all those Argentinians, and I didn't renew my season ticket. Thousands of supporters did likewise, because we wanted to protest. The stadium was practically empty on matchdays. The exodus of fans following Grinbank's arrival was enormous."

The results were disappointing as well, and the new owner realised that his dream was not going to be achieved easily. Chamot only played once for the last club in his career, as a substitute in the traumatic 3-1 home defeat to Sporting Gijon. Having understood that he was unwanted, Grinbank decided to abandon the project in January 2004.

"It took him no more than 10 minutes to say goodbye," coach Carlos Aimar said. "We don't have an idea what to do."

Two weeks later, Aimar left. The club tried to install Pekerman in his place, but were refused by the FA, because the Argentine maestro bizarrely couldn't present the relevant experience, having only managed youth sides until then. With the club in serious financial trouble, all the players were offered to cancel their contracts or renegotiate them at lower wages. It was total chaos, and nobody was surprised when Leganes were eventually relegated on the final day of the season.

To make matters much worse, local rivals Getafe had been promoted to the Primera Division for the first time in their history in the very same season. The rivalry between the two neighbouring towns just south of Madrid is fierce, and it's not limited only to sports. Fans watched in horror as Getafe gradually became a respected outfit in the top flight, signed famous coaches like Michael Laudrup, and even had a very decent run in Europe, reaching the UEFA Cup quarterfinals in 2008.

Meanwhile, Leganes spent 10 long seasons in the third division. They were even nearly relegated to the fourth tier as recently as 2012.

Life can be very ironic, though, and the circle was closed in hilarious fashion. Getafe, who never really managed to attract a significant following, were relegated last season. At the same time, Leganes were sensationally and unexpectedly promoted, finishing second in the Segunda Division with the best attacking record in the league. They were triumphant because they did it the right way this time, and fans are incredibly proud of their humble and dedicated players.

"When we were relegated in 2004, I renewed my season ticket in order to help the team in difficult situation," Sanchez says. The Pavon family took over at the troubled club, and Maria Victoria Pavon became the first female president in its history in 2009. Leganes stopped overspending, kept small, healthy budgets and built their squad around committed players; they might not have been the most technically gifted, but certainly the most tactically disciplined. In short, that was exactly the team the fans could identify with.

Asier Garitano has been perfect for that strategy. The little-known coach, who had a mediocre playing career in lower divisions, arrived at Leganes in 2013 and proved to be a miracle worker. The team was promoted to the second division in 2014, and just two years later were strong enough to keep pace ahead of everyone on their way to history.

Remarkably, two of the team's best performers are Argentinians, but they have totally different background to those who were signed by the club in 2003.

When Martin Mantovani came to Madrid a decade ago, he had no money and was forced to sleep in the street while trying to get a chance at Atletico. He never really made it and his career looked in ruins when Garitano gave him an opportunity in 2013. Three years later, the 32-year-old centre-back is the proud captain of Leganes, and he even dyed his hair blue to celebrate the incredible promotion.

Striker Alexander Szymanowski also comes from a poor family and had little luck in the beginning of his career, playing for tiny clubs until the age of 24. He never lost hope, though, and flourished at Leganes last season, scoring 12 goals in an outstanding campaign. Now the fans expect him to set La Liga alight with his skills.

Mantovani, Szymanowski and the excellent goalkeeper Jon Ander Serantes, who worked as a bricklayer in his youth, are the true representatives of Leganes. They don't have stars, but they work harder than anyone, and their start in the top flight has been absolutely sensational.

On their debut in the Primera Division, Leganes won 1-0 at Celta Vigo. Right-back Victor Diaz, the 28-year-old journeyman who played for Celta reserves in 2011-12 and was released, scored the only goal.

The first home game was against the big neighbours Atletico, a second team of many Leganes fans who never had to choose between the two until now. That dilemma was easily solved, and everyone supported Pepineros, the Cucumber Growers, as their defensive efforts were rewarded with a goalless draw.

The first defeat -- albeit rather unlucky -- eventually came at Gijon last Sunday, and Leganes conceded their first goals in the top flight, but now they are ready for the biggest game in the modest history of Estadio Municipal de Butarque. The mighty Barcelona are about to visit on Saturday, fresh after the 7-0 thrashing of Celtic in the Champions League, with Lionel Messi, Neymar and Luis Suarez in sparkling form.

The hosts' chances might look slim, but Pepineros believe in themselves, and the two clubs remarkably share a famous former player. Samuel Eto'o started his career in Spain at Leganes, on loan from Real Madrid in 1997-98, and the 16-year-old Cameroonian didn't make an impression, scoring just four goals. The fans followed him ever since, and were proud of his achievements at Barcelona.

Now, at long last, they have arrived to the big stage themselves, and it will be very unwise to underestimate the power of Leganes' will.